This invention relates generally to restorative dentistry and more particularly to bar overdenture systems.
Implant prosthetic systems include a variety of restorations, such as single tooth, partially edentulous and edentulous. One type of prosthetic system employs the use of a bar overdenture. This system comprises a conventional acrylic denture retained by suitable attachments such as clips or the like to an implant supported cast bar. A conventional procedure for implanting the support structure involves a number of office visits as well as laboratory participation. For example, once root implants have been placed in the alveolar ridge and sufficiently healed, threaded healing abutments are removed and appropriate abutments are inserted and tightened with a special torque wrench. Impression posts are inserted with a friction drive wrench and an impression is made from suitable material such as polyvinylsiloxane for transferring abutment locations to a laboratory model or analog. The impression posts are then removed and threaded onto the abutment analog. The analog is then inserted into the impression and a model is poured in the laboratory. The model is then separated from the impression and impression posts are removed with a friction drive wrench. Bar copings are then placed over the analog in the model and secured with special coping screws. A connecting bar is waxed between bar copings, sprues are attached, coping screws removed, the model is invested and cast. The casting is then tried in the model and adjustments made including a new impression if necessary. A passive and precise fit is essential to avoid subsequent implant failure. Polishing caps and metal finishing are completed and the casting is returned to the restorative dentist to try intraorally to confirm a passive fit. Finally the bar is seated over the abutments and tightened thereto with a torque wrench. The denture is then seated over the bar.